Method for dehydrating, without decomposition, hydrated salts



Patented Aug. 1, 1933 V r V H 1,920,289 METHOD 'FOR DEHYDRATING, WITHOUT DECOMPOSITION, HYDRATED SALTS.

7 Harold Simmons Booth and Gilberta G. Torrey, Cleveland Heights, Ohio NO Drawing. Application June 26, 1930 Serial No. 4 4,105

3 Claims. (o1. 23-50.)

This invention relates to method for the. preparation of anhydrous salts, or in other words,-

the dehydration of salts which normallyjin crystalline form carry one or more molecules of water of crystallization. I v

The invention is particularly'directedto the preparation of anhydrous salts, which, bynormal methods of dehydrationbecome decomposed. A particularly important use of such dehydrated 10 salts is in connectionwith the use of such salts in the electrodeposition of metals from liquid ammonia, wherein salts of'certain metals, as for instance beryllium, are far preferable for use, in anhydrous form rather than in hydrated form. Without in any way limitingthe scope of the invention, we will proceed with the'idescrip tion of the invention, largely utilizing beryllium salts as an example, although'it is but oneof many examples of metals and semi-metals whose salts lend themselves to this practice. W ,7 Perhapsthe best known salt of beryllium is the nitrate'which normally carries with :it four molecules of water. Treatment of this salt' to dehydrate the'same by means of heat or vacuum, causes decomposition of the salt to a basic nitrate, oxides of nitrogen beinggiven off simultaneously with the water. V I

In dehydrating beryllium nitrate by the method of this invention, we would melt ammonium niberyllium nitrate into the fused bath. Under f such circumstances dehydration of the beryllium nitrate takes place under conditions which prevent release Of nitrogen Oxides from the beryllium salt, and, therefore, maintain normal beryllium nitrate. a

The ammonium nitrate gradually becomes decomposed under heat, and the final mass is principally anhydrous beryllium nitrate with a relatively small and unimportant amount of ammonium nitrate.

For most purposes this ammonium nitrate would in no way be objectionable in the contem- ;-in using the dehydrated beryllium nitrate for the electrodeposition of beryllium from liquid ammonia, the ammonium nitrate would not only be not disadvantageous, but would have a distinct advantage in that it raises the solubility of the nitrate in the liquid ammonia.

The nitrates of metals are not the only salts.

which canbe so treated, but identically the same type of reaction can be used in the case of acetates,

thiocyanates and similar salts. 5

In proceeding with the dehydration of salts other than nitrates, the preferable way would be to use an ammonium salt of the same acid radical as the salt to "be dehydrated, for instance, if the salt to be dehydrated is an acetate, to use ammonium acetate, and similarly with other salts.

Where the presence of extraneous ions is not objectionable, in the dehydrated salt, it is quite possible to use ammonium salt of an acid different from the acid of the salt to be dehydrated, thus the same salt might be used for the dehydrationof' a thiocyanate, a cyanide, a halide or any other salt which does not lend itself to ready dehydration by usual methods.

As we have before pointed'out the reference to so beryllium was merely taken for convenience, and we have found that our process is equally operative with salts of aluminum, chromium, zirconium, thorium and many other similar metals which form salts having water of crystallization.

. Having thusdescribed our invention, we claim:

1. The method of dehydrating a hydrated salt, which consists in introducing the salt to be dey hydrated into a bath of fused ammonium salt.

' 2; The method of dehydrating a hydrated salt, which consists in introducing the salt to be dehydrated into a fused bath of an ammonium salt of the same acid as the salt to be dehydrated.

3. The methodof dehydrating beryllium'salts which consists in introducing the beryllium salt into a fused bath of an ammonium salt.

HAROLD SIMMONS BOOTH,

GILBERTA G. TORREY. 

